1. Field of the Art
This invention relates to endoscopic insertion instruments of the sort which has an endoscopic insertion rod extended out from a manipulating or gripping head and which includes, successively from a proximal end, a rigid rod section, a flexible rod section, an angle section and a distal end section as in the case with vaginal endoscopes, and more particularly to a removable protector sheath to be fitted on such an endoscopic insertion instrument to prevent buckling or similar damages to the flexible rod section particularly in its end portions connected to a rigid rod section of the insertion instrument.
2. Prior Art
Generally, endoscopic insertion instruments are largely constituted by a manipulating or gripping head and an insertion rod extended out from the manipulating head for insertion into an internal canal of a patient or other intracavitary portions to be examined. By the nature of the insertion instrument, endoscopes can be categorized into a rigid or hard type employing an insertion instrument in the form of a rigid structure, and a flexible or soft type employing an insertion instrument in the form of a flexible structure except for an angle section and a distal end section which are connected to the fore end of a flexible insertion rod. Further, in some endoscopes, the insertion instrument is provided with a rigid rod section of a certain length from its proximal end, which is connected to a manipulating head, in addition to a flexible rod section, an angle section and a rigid distal end section as mentioned above.
Among various types of endoscopes with different insertion rod constructions, the vaginal endoscope is typical of the endoscopes which are provided with a rigid-flexible insertion instrument having a rigid rod section at a proximal end of an insertion rod or between a flexible rod section and a manipulating head of the instrument. In the case of a vaginal endoscope, by its nature, an actual insertion length is relatively short as compared with the total length of the insertion rod, which is usually provided in an ample length to permit the operator to handle the manipulating head at a suitable distance from the patient body. In this connection, the operator would face problems of instability and inferior maneuverability of the instrument if the insertion rod were made flexible over its entire length a major proportion of which always remains outside the patient body. Therefore, it has been the general practice to use a rigid pipe structure or the like in a proximal portion of the insertion rod between a manipulating head and a flexible rod section and to interpose an angle section between the flexible insert portion and a rigid distal end section thereby to turn endoscopic observation means on the rigid distal end section into directions of particular interest.
Once introduced into patient body for examination or diagnostic purposes, the endoscopic insertion instruments is contaminated by contact with body fluids and therefore needs to be washed clean after each use. In this regard, the general procedure has been to wash used endoscopic insertion instruments by immersion in a cleaning liquid in a washing sink which is equipped with a clean water tap along with a closed spent water drainage system exclusively for this purpose. Washing equipments of this sort are normally installed in a cleaning room or station other than an endoscopic examination room or rooms, so that used endoscopes have to be collected from an examination room or rooms and taken to the cleaning station by hand for immersion in the cleaning liquid.
The endoscopic insertion rod of this sort contains at least a light guide and an image transfer means, for example, an image guide in the case of an optical endoscope or a signal cable in the case of an electronic endoscope having a solid-state image sensor fitted in an observation window at the distal end of the insertion rod. In many cases, the insertion rod further accommodates a biopsy channel for insertion of bioptic instruments such as forceps or the like, and a fluid conduit tube for feeding a fluid medium to a fluid outlet at the distal end of the insertion rod. In the flexible rod portion of the instrument, generally all of these component parts are fitted in a tubular flexible structure, which is constituted by, for example, one or a plural number of layers of helical coil tubes, metal wire netting wrapped around the helical coils tubes, and an outer skin layer formed on the exterior side of the metal wire netting. Any way, the flexible rod section of the insertion instrument is arranged in such a manner as to have a relatively high degree of flexibility in order to guarantee free bending flexures in arbitrary directions along paths of insertion, and directly connected to rigid rod sections of the insertion instrument at its fore and rear ends. Therefore, the rigidity of the insertion rod changes drastically across the joints of the flexible and rigid rod sections.
After use, a contaminated endoscope is picked up by one of cleaning staff and, for an immersed cleaning treatment in a washing sink as mentioned hereinbefore, taken to a cleaning room or station where cleaning equipments are installed, gripping the endoscope particularly by a rigid rod section which has not been introduced into patient body, for example, by a manipulating head portion, a rigid rod section of the insertion rod and/or a light guide cable connected to the manipulating head of the endoscope, while paying attention not to touch either insertion rod portions forward of the flexible rod portion, which have been contaminated with body fluids, including the rigid tip end portion at the distal end of the flexible rod section nor rigid rod portions immediately adjoining the flexible rod section. In handling contaminated endoscopes in this manner in a post-examination stage, there are always possibilities of the tip end section of the insertion rod or other fragile or vulnerable part of the endoscope being hit against hard surfaces of nearby objects or structures or against walls or other parts of the washing sink.
When hit against a sink wall or other hard surfaces, rigid portions of an endoscopic insertion rod would not sustain any material damages unless the collisional impact is of an extraordinarily large magnitude, in contrast to the flexible rod portions which are easily bent by collisional impacts. Especially at a joint of flexible and rigid rod sections, which have conspicuously different rigidities, it is very likely that the flexible side of the rod be abruptly bent at the time of collision and as a result forcibly deformed or buckled to an abnormal degree. This is very much so in the case of a vaginal endoscope with a relatively narrow flexible rod section on the insertion rod, employing helical coils of lower strength as a flexible structural for the flexible section. When bent forcibly, a narrow flexible rod portion of this nature is susceptible to buckling or deformation to such a degree as would cause breakage or other damages to the component parts which are fitted in the flexible rod section, for example, breakage of fiber optics of a light guide or of an image guide.